DelDOT Development Coordination Manual Highlighted text is for guidance purposes. TABLE OF CONTENTS CHAPTER 5 DESIGN ELEMENTS 5-1 5.1 GEOMETRIC DESIGN OF SUBDIVISION STREETS ..................................................... 5-1 5.1.1 Geometric Design of Subdivision Streets - General............................................................ 5-1 5.1.2 Geometric Design of Subdivision Streets - Design Criteria ................................................ 5-2 5.1.3 Geometric Design of Subdivision Streets - Intersection Design ......................................... 5-2 5.1.4 Geometric Design of Subdivision Streets - Parking Provisions .......................................... 5-6 5.1.5 Geometric Design of Subdivision Streets - Dead End Streets ............................................ 5-6 5.1.5.1 Permanent Dead End Streets ..................................................................................... 5-6 5.1.5.2 Temporary Dead End Streets ..................................................................................... 5-7 5.1.6 Geometric Design of Subdivision Streets - Traffic Calming ............................................ 5-11 5.2 SUBDIVISION AND COMMERCIAL ENTRANCE DESIGN GUIDELINES .............. 5-11 5.2.1 Subdivision and Commercial Entrance Design Guidelines –Process................................ 5-13 5.2.2 Subdivision and Commercial Entrance Design Guidelines – Entrance Location ............. 5-14 5.2.3 Subdivision and Commercial Entrance Design Guidelines – Design Vehicle .................. 5-16 5.2.4 Subdivision and Commercial Entrance Design Guidelines – Entrance Width .................. 5-17 5.2.5 Subdivision and Commercial Entrance Design Guidelines – Intersection Corner Radii .. 5-19 5.2.5.1 Simple Curve Radius ............................................................................................... 5-22 5.2.5.2 Simple Curve Radius with Taper............................................................................. 5-25 5.2.5.3 Three Centered Compound Curves ......................................................................... 5-27 5.2.5.4 Turning Roadways .................................................................................................. 5-29 5.2.5.5 Channelizing Islands ............................................................................................... 5-35 5.2.5.6 Turning Movement Diagrams ................................................................................. 5-37 5.2.6 Subdivision and Commercial Entrance Design Guidelines – Entrance Length ................ 5-38 5.2.7 Subdivision and Commercial Entrance Design Guidelines – Horizontal Alignment ........ 5-40 5.2.8 Subdivision and Commercial Entrance Design Guidelines – Vertical Alignment ............ 5-41 5.2.9 Subdivision and Commercial Entrance Design Guidelines – Auxiliary Lanes ................. 5-44 5.2.9.1 Right-Turn Lane ...................................................................................................... 5-44 5.2.9.2 Bypass Lane ............................................................................................................ 5-46 5.2.9.3 Left-Turn Lane ........................................................................................................ 5-51 5.2.9.4 Crossover ................................................................................................................. 5-56 5.2.10 Subdivision and Commercial Entrance Design Guidelines – Bike Lanes ........................ 5-61 5.3 PEDESTRIAN FACILITIES ................................................................................................ 5-61 5.3.1 Pedestrian Facilities - Sidewalks....................................................................................... 5-61 5.3.1.1 Placement ................................................................................................................ 5-61 5.3.1.2 Material ................................................................................................................... 5-62 5.3.1.3 Ramps ................................................................................................................................. 5-62 5.3.2 Pedestrian Facilities - Shared Use Path ............................................................................. 5-64 5.3.2.1 Design Criteria ........................................................................................................ 5-64 5.3.2.2 Intersections............................................................................................................. 5-64 5.3.3 Transit Stop Design ........................................................................................................... 5-65 5.4 SIGHT DISTANCE ...............................................................................................................5-65 5.5 TYPICAL SECTIONS ......................................................................................................... 5-67 5.5.1 Typical Sections - Pavement Widths ................................................................................ 5-67 5.5.2 Typical Sections - Curbs .................................................................................................. 5-68 5.5.3 Typical Sections - Ditches and Sideslopes ....................................................................... 5-73 i Design Elements Effective November 2019 DelDOT Development Coordination Manual TABLE OF CONTENTS 5.5.4 Typical Sections - Underdrains ......................................................................................... 5-73 5.5.5 Typical Sections - Clear Zone .......................................................................................... 5-74 5.5.6 Typical Sections – Lateral Offset ......................................................................................5-74 5.6 PAVEMENT SECTIONS .................................................................................................... 5-77 5.6.1 Pavement Sections - Subdivision Streets .......................................................................... 5-78 5.6.2 Pavement Sections - Entrances ......................................................................................... 5-80 5.6.3 Pavement Sections Industrial Streets / Entrances ............................................................. 5-81 5.6.4 Pavement widening ........................................................................................................... 5-81 5.7 SUBDIVISION DRAINAGE DESIGN ................................................................................... 5-83 5.7.1 Subdivision Drainage Design - General ............................................................................ 5-83 5.7.2 Subdivision Drainage Design - Drainage Criteria ............................................................ 5-83 5.7.2.1 Open Channels ........................................................................................................ 5-83 5.7.2.2 Culverts ................................................................................................................... 5-83 5.7.2.3 Storm Sewers ........................................................................................................... 5-84 5.7.2.4 Inlet Design ............................................................................................................. 5-85 5.7.2.5 Pipe Cover ............................................................................................................... 5-85 5.7.2.6 Drainage Easements ................................................................................................ 5-86 5.7.2.7 Drainage Design Report .......................................................................................... 5-87 5.7.2.8 Safety Grate for Pipe Inlet ....................................................................................... 5-88 5.7.3 Subdivision Drainage Design - Hydrology ....................................................................... 5-88 5.7.4 Subdivision Drainage Design - Hydraulics ....................................................................... 5-88 5.8 STORMWATER MANAGEMENT .................................................................................... 5-89 5.9 EROSION AND SEDIMENT CONTROL ......................................................................... 5-90 5.10 STRUCTURAL DESIGN .......................................................................................................... 5-90 5.11 SIGNING AND PAVEMENT MARKING DESIGN ............................................................ 5-91 5.11.1 Signing and Pavement Marking Design-Signing ............................................................ 5-91 5.11.1.1 Placement of Signs .................................................................................................. 5-91 5.11.1.2 Specifications .......................................................................................................... 5-91 5.11.1.3 Signs Required in Residential Development ........................................................... 5-91 5.11.2 Signing and Pavement Marking Design - Pavement Markings ........................................ 5-93 5.12 MAINTENANCE OF TRAFFIC ..........................................................................................5-93 5.13 SIGNAL DESIGN....................................................................................................................... 5-94 5.14 UTILITY DESIGN ...............................................................................................................